This invention relates to novel compositions of matter containing optically pure (-) amlodipine. These compositions possess potent activity in treating both systolic and diastolic hypertension while avoiding adverse effects including but not limited to edema of the extremities, headache and dizziness, which are associated with administration of the racemic mixture of amlodipine. Additionally, these novel compositions of matter containing optically pure (-) amlodipine are useful in treating angina and such other conditions as may be related to the activity of (-) amlodipine as a calcium channel antagonist including but not limited to cerebral ischemia, cerebral disorders, arrhythmias, cardiac hypertrophy, coronary vasospasm, myocardial infarction, renal impairment and acute renal failure--while avoiding the adverse effects associated with administration of the racemic mixture of amlodipine. Also disclosed are methods for treating the above-described conditions in a human while avoiding the adverse effects that are associated with the racemic mixture of amlodipine, by administering the (-) isomer of amlodipine to said human.